Internal-combustion engine



March 3, 1931. STUART. 2 1,795,099

INTERNAL comausnon ENGINE Filed Dec. 28. 1928 m o A j 6 .1 a t j z y n P[7? J [7 17 a 1 i g I vlrrwiwir-s.

Patented Mar. 3, 1931 UNITED STATES PATENT OFFICE JOSEPH STUART, 2B, OFWILMINGTON, DELAWARE, ASSIGNOR or ONE-HALF 'ro ALFRED I. DU PONT, orJACKSONVILLE, FLORIDA INTERNAL-COMBUSTION ENGINE.

Application filed December 28, 1928. Serial No. 328,945.

In internal combustion engines it is desirable, in order to securemaximum efficiency,

to expel all the exhaust gases from the cylinder at the completion ofthe explosion stroke. Difiiculty has been experienced in effecting athorough expulsion of exhaust gases.

The object of my invention is to provide means for effecting a certainand thorough expulsion of exhaust gases. This I have accomplished bycausing air to be blown completely through a plurality of cylinderssuccessively and out'the last cylinder, thereby insuring that allexhaust gases in all the cy inders will be driven ahead of the air andblown out of the last cylinder. The application of my invention toengines of known types involves certain practicable modifications in theconstruction of the engine, which modifications, however, do nototherwise effect their efficiency.

The figure isan elevation, largely in section, of one embodiment of myinvention.

The embodiment of the invention shown is a two cycle engine having twocylinders a and 6, arranged side by side, their plstons, 0

and cl, reciprocating in unison in the same di-.

rection. The pistons are connected with the crank shaft (not shown) inthe crank case f. The ends of the two cylinders in which air iscompressed and fuel admitted should com municate with one another. Thiscan be effected by different means, but it is preferred to provide thecylinders with a common compression chamber 6, which communicates with afuel feed pipe g.

The intermittent admission of fuel may be controlled by a needle valveh, which may be operated by a rock lever i which, through areciprocating rod 1', may be operated from a cam k on the crank shaft oron a shaft driven therefrom.

The engine may be of the Diesel type or may be provided with a sparkplug m The cylinder (1, between its ends, is provided with air admissionports n. The cylinder 6, between its ends, is provided with gas and airexhaust ports 0. The ports n and 0 should be so located and the pistonsshould be of such length that the ports, and particularly the ports a,will be at all times covered except near and at the end of the expansionstroke.

Ports 0 may have free communication with the atmosphere. Ports ncommunicate with a pipe p connected with an air charging device 1',which may be an air compressor or centrifugal blower or any deviceadapted to blow air through the pipe 79 at a predetermined pressure.This air feed device may be actuated, directly or indirectly, from thecrank shaft through any suitable gearing s. It may be operatedconstantly to build and store up air pressure, or it may be operatedintermittently to forcibly blow air through pipe p when ports n areuncovered.

Near the end of the expansion stroke of the pistons they uncover bothsets of ports a and 0 am air rushes through ports a, and thence from onecylinder to another and out ports 0, thereby thoroughly scouring thecylinders of all exhaust gases.

No part of the exhaust gas can be driven toward a dead end of eitherpiston and lodge there while the scouring fluid is flowing through thecylinders; but the entire volume of gas is driven ahead of the airtoward and out of ports 0 until it has expelled the gas from bothcylinders. To insure this action the communication between the cylindersmay be as restricted as may be found necessary.

It may be desirable, in certain cases, to place in the pipe p a suitabletimed valve :10, protected from heat by the intermittently formed deadair space y, and operable from mechanism 10, which may be actuated from(say) the shaft carrying the cam is. If ports a are of such length or sopositioned as to close shortly after ports 0, this allows the incomingair to be pre-compressed after exhaust ports 0 have been closed. Thisfeature is of value, and may be essential, in engines operating at highaltitudes.

It is clear, from the foregoing description, that by means of thedescrlbed construction, or such modifications thereof, consistent withthe principle of the invention, that may be developed by skilledengineers, both engine cylinders will be thoroughly denuded of exhaustgases by the time the pistons have fairly started on their compressionstroke. hat I claim and desire to protect by Letters Patent is An enginecomprising a plurality of cylinders, the fuel intake ends of twocylinders being in communiG ition, one of said cylin+- ders having a gasexhaust port and the other of said cylinders having an air admissionport, means to blow air through the lZLS port,

and pistons in said two .cyl lfll lh rs,theele ments being so arrangedthat the pistons of said two cylinders move together in the. same phasein their expansion strokes and their compression strokes andgHQQOVersaidports at the end portions of their expansion strokes, whereby air isblown into and through one cylinder and thence into, through and out ofthe other cylinder, the air admission port being positioned to beclosed,-in the compression stroke of the piston, afterthe gas exhaustport is closed to allow pro-compression of air-after the closure of thegas exhaust port and before the closure of the air inlet port, and atimed valve controlling the admission of air through said air admissionport.

In testimony of which invention, I have hereunto set my hand, atWilmington, Dela ware, on this 24th day of December, 1928.

' JOSEPH STUART, II.

